The present invention relates to an evaporator used in a car air conditioner, which is a refrigeration cycle to be mounted on an automobile, for example.
In this specification and appended claims, the downstream side (a direction represented by arrow X in FIG. 1 and the right sides of FIGS. 4 to 6) of an air flow through air-passing clearances between adjacent heat exchange tubes will be referred to as the “front,” and the opposite side as the “rear.” Further, the upper, lower, left-hand, and right-hand sides as viewed frontward from the rear side (the upper, lower, left-hand, and right-hand sides of FIG. 1) will be referred to as “upper,” “lower,” “left,” and “right,” respectively.
The present applicant has proposed an evaporator which satisfies the requirements for reduction in size and weight and higher performance (refer to Japanese Patent Application Laid-Open (kokai) No. 2005-164226). The evaporator includes a refrigerant inlet header section and a refrigerant outlet header section juxtaposed in the front-rear direction, and a refrigerant circulation path for establishing communication between the two header sections. The refrigerant circulation path includes a first intermediate header section disposed to face the refrigerant inlet header section, a second intermediate header section disposed rearward of the first intermediate header section to face the refrigerant outlet header section, a plurality of heat exchange tubes disposed between the refrigerant inlet header section and the first intermediate header section, and a plurality of heat exchange tubes disposed between the refrigerant outlet header section and the second intermediate header section. A refrigerant inlet is formed at one end of the refrigerant inlet header section, and a refrigerant outlet is formed at one end of the refrigerant outlet header section, the one end being located on the same side as the refrigerant inlet. Refrigerant having flowed into the refrigerant inlet header section through the refrigerant inlet passes through the refrigerant circulation path, and reaches the refrigerant outlet header section, from which the refrigerant is fed out through the refrigerant outlet. A pipe joint plate which has a refrigerant inflow portion assuming the form of a short tube and communicating with the refrigerant inlet, and a refrigerant outflow portion assuming the form of a short tube and communicating with the refrigerant outlet is joined to the refrigerant inlet header section and the refrigerant outlet header section to extend over the header sections. An end portion of a refrigerant inlet pipe is inserted into and joined to the refrigerant inflow portion, and a diameter-reduced end portion of a refrigerant outlet pipe which is larger in diameter than the refrigerant inlet pipe is inserted into and joined to the refrigerant outflow portion.
Although not illustrated, in the evaporator disclosed in the publication, the refrigerant inlet pipe and the refrigerant outlet pipe are bent frontward; an expansion valve attachment member is joined to end portions of the two pipes such that the expansion valve attachment member extends over the pipes; and an expansion valve is attached to the expansion valve attachment member. The opening of the expansion valve is adjusted on the basis of the temperature and pressure of the refrigerant which flows through the refrigerant outlet pipe after having flowed out of the interior of the refrigerant outlet header section.
However, in the evaporator disclosed in the publication, since the refrigerant inlet pipe and the refrigerant outlet pipe are bent through bending work, there is a limit on reducing the radius of curvature of the refrigerant inlet pipe and the refrigerant outlet pipe. Therefore, the evaporator has a problem in that the expansion valve cannot be disposed near the evaporator.